E 150 1/2 Ton Van V6-4.2L VIN 2 (1997)
Canister Purge Control Valve: Description and Operation
EVAP Canister Purge Valve
PURPOSE
The Vapor Management Valve (VMV) controls the flow of vapors (purging) from the fuel vapor storage canister to the intake manifold during various
engine operating modes.
OPERATION
The PCM outputs a variable duty cycle signal (between 0 and 100%) to the VMV solenoid to either divert more vacuum to the valve part of the VMV
and open it, or vent more vacuum to the atmosphere at the solenoid and close the VMV. The increase in vacuum acting on the VMV diaphragm
overcomes the valve spring and begins to lift the VMV pintle oft its seat, causing fuel vapor flow into the intake manifold.
FEATURES
The VMV is designed to compensate for changes in the intake manifold that is applied to the solenoid part of the VMV, and it will maintain a constant
vapor flow at any given duty cycle for manifold vacuums between 16-67 kPa (5-20 in-Hg).
